Well APL is great but it is write-only. Also naming is hard, but in APL it is very easy: you just don't do it. What does the following do?

    program ← {⊃1 ⍵ ∨.∧ 3 4 = +/ +⌿ ¯1 0 1 ∘.⊖ ¯1 0 1 ⌽¨ ⊂⍵}

Libraries in other languages deal with arrays just fine, and can solve actual problems at internet scale. Like numpy/jax, or pytorch, which will compile your code to clusters of TPU/GPUs. Most of the useful primitives of APL are present in these libraries (iota, reshape, reduce, etc[1]). The function composition primitives in APL are fine from a theoretical viewpoint, but I can't help feeling like I'm dealing with some obfuscation language crafted by academia to protect some fiefdom. Is it really that interesting to have a primitive for swapping arguments? Isn't that in the domain of conventions? APL was used by algorithmic trading companies for interviewing; just like Google wants you to go through Leetcode only to never use that kind of programming again.

Also APL/BQN/I/J/K all lack an auto-differentiation primitive, which is sort of a shame for 'functional' languages. Functions are mathematical objects too!

But if you just want a code golf session, then I guess APL is just fine. It also may improve your functional abstraction thinking.

/yelling at cloud, I'll go back to my cavern now

[1] https://jax.readthedocs.io/en/latest/jax.lax.html

The lack of an AD primitive is something I've discussed with the creator of BQN, coming from a JAX world I really miss it and feel that it's such an obvious feature, especially in a language which has a way to turn a tacit function into its AST[1], which has been used for symbolic differentiation[2]. Going from symbolic to reverse-mode AD is not much of a leap and users can define their own primitives with ReBQN[3].

I see what you mean by obfuscation, but I think that it's one of those things that feels really hard and stupid until you start being able to do it really quickly. When you learn a foreign language, you first read letters, then words, then sentences because you become accustomed to larger pieces of the language that you can predict what's coming next without reading it. A similar sort of thing happens with APL/BQN, you read letters (primitives), then you begin to recognise words (small, commonly used groups of primitives), then you see larger patterns which look like magical incantations to an inexperienced user.

These "words" are (typically) tacit phrases, many of them only existing due to specific primitives like swap. Once I used BQN to golf, I started wishing Julia had a swap for operators i.e.

  -(3, 5) = -2
  swap(-)(3, 5) = 2

I won't defend these languages to the death, but they are fun to puzzle your brain with in codegolf. Maybe Dex[4] will go somewhere too.

[1]: https://mlochbaum.github.io/BQN/spec/system.html#operation-p...

[2]: https://saltysylvi.github.io/blog/bqn-macros.html

[3]: https://mlochbaum.github.io/BQN/doc/rebqn.html

[4]: https://github.com/google-research/dex-lang